I can give you several sentences.
A slogan is supposed to be catchy.
Only if it is a name or the first word in a sentence.
No, except if the word is used at the beginning of a sentence.
I was supposed to go home. I did, however, wait until dinner had finished. It was a good decision, because after dinner, we enjoyed an excellent dessert!
They were SUPPOSED to be together.
They were supposed to give me an answer by now. Where were we going? We Americans were then over there.
IN your sentence, is the word "to" supposed to be 2?
I'm not sure who's supposed to be at bat next.
Meet me at the rendezvous point, immediately. We were supposed to rendezvous at nine.
People think the last word of the sentence is booty
The last lines of the inscription on the grave are a bitter reference to carey's supposed cowardice.
Only if it's the first word or someone's name. It's not a proper noun.